The objective of this study is to determine the safety and immunogenicity of an improved two-vial formulation of CHO cell-derived HIV-1 SF-2 rgp120 envelope vaccine formulated with MF59 adjuvant emulsion when administered to healthy HIV-1 uninfected volunteers. Prior formulations had suboptimal stability or were impractical (requiring storage at -70 degrees C). Therefore, an improved formulation has been developed that is expected to be more practical and stable, to allow studies of this expanded vaccine candidate or analogous candidates designed for other geographic regions.Our goal is recruitment of sufficient volunteers and following their long term progress.